<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html lang="en">
<head>
	<meta http-equiv="Content-Type" content="text/html;charset=UTF-8">
	<title>Document</title>
	<style type="text/css">
    .box{

    	width: 600px;
    	height: 600px;
    	background: red url() 0 0 no-repeat;
    	margin: auto;
    	margin-top: 100px;
    }
    .box1{
    	width: 500px;
    	height: 500px;
    	background: yellow url() 0 0 no-repeat;
    	margin-left: 100px;
    }
    .box2{
    	width: 100px;
    	height: 100px;
    	background: green url() 0 0 no-repeat;
    	float: left;
    	margin: 10px;
    }
    .box3{
    	width: 120px;
    	height: 120px;
    	background: green url() 0 0 no-repeat;
    }
    .box4{
    	width: 100px;
    	height: 100px;
    	background: green url() 0 0 no-repeat;
    	float: right;
    }
	</style>
</head>
<body>
	<div class="box">
		<div class="box1">
		<div class="box2">1</div>
		<div class="box2 box3">2</div>
		<div class="box2 box4">3</div>
		<div class="box2">4</div>
		</div>
	</div>
</body>
</html>